We construct solutions to the nonlinear magnetic Schr\"odinger equation {−ε2ΔA/ε2u+Vuu=∣u∣p−2u=0inΩ,on∂Ω, in the semiclassical r\'egime with strong magnetic fields. In
contrast with the well-studied mild magnetic field r\'egime, the limiting
energy depends on the magnetic field allowing to recover the Lorentz force in
the semi-classical limit. Our solutions concentrate around global or local
minima of a limiting energy that depends on the electric potential and the
magnetic field. The results cover unbounded domains, fast-decaying electric
potential and unbounded electromagnetic fields. The construction is variational
and is based on an asymptotic analysis of solutions to a penalized problem in
the spirit of M. del Pino and P. Felmer.Comment: 23 pages, minor correction